Positioning features of vocal, semantic, and graphemic task zones in Chinese-English bilinguals

Background: Bilinguals are people that can use two languages for oral communication. Many bilinguals have specific language-associated cortical regions. This study aimed to analyze the cortical positioning features of vocal, semantic, and graphemic task zones in unskilled late Chinese (first)-English (second) (ULCE) bilinguals using the blood-oxygen-level dependent functional magnetic resonance imaging (BOLD-fMRI) technique. Methods: Twelve ULCE bilinguals were assigned Chinese-English (C-E) vocal, semantic, and graphemic tasks; SPM8 software was used to compare and investigate the brain activation maps towards different language tasks and to calculate their corresponding lateralization indexes (LIs). Results: These three language tasks in simple Chinese could activate most traditional language zones, which all exhibited obvious left-deviated activation dominance. A simple English task could also activate most traditional language zones, but only the semantic task appeared to have obvious left-deviated lateralization. However, none of the three tasks displayed any specific language zones between Chinese and English on the group level. Conclusions: Vocal, semantic, and graphemic tasks can all activate multiple brain regions in the language network and reflect their respective cognitive processing characteristics. Bilingual processing in ULCE bilinguals has similar neural mechanisms, but the left-deviated lateralization is not obvious when performing English vocal and graphemic tasks.